this is how I made my own Hohner 114 treble springs:
I broke two of them and was unable to find replacement ones.
I bought piano string in various gauge, 0.70mm was too hard, 0.65mm was OK for me, original were 0.67mm .
The high tech build machine is made of two piece of wood, nuts, and axle is a 2mm drill bit .
Tighten the end of the wire into the rotating arm
The wire needs to be lightly pressed between the two pieces of wood
to create tension,
Put the arm on the axle, the wire over the axle,
press firmly the arm against the base-plate, and rotate.